It is well known that the direction of magnetization of a magnetic material can be reversed or switched by impressing an external magnetic field of opposite polarity upon the material. Typically, magnetic material may be placed upon a nonmagnetic substrate and then divided or separated by a grid-like pattern to create magnetic post elements. When electric conductors are placed within the separations which form the grid-like pattern, electric currents may be passed through the conductors to generate a magnetic flux about each conductor. This flux is concentrated at the intersection of two conductors in two of the four quadrants formed by the intersection. Through the utilization of a low anisotropy material located within one of the two quadrants in which the flux is concentrated, it is possible to control which magnetic post element will be switched at each intersection.
The technique of utilizing a grid-like pattern to switch the direction of mangetization of a magnetic element is known in bubble domain structures, see for example, U.S. Pat. No. 4,114,191, issued Sept. 12, 1978, by R. E. Lund, entitlted "Bubble Domain Structuring In Bubble Domain Memory Plane." It is also known to utilize a grid-like pattern formed upon a transparent nonmagnetic substrate by separations of a transparent magnetic coating to form a magneto-optic device; see example, British Pat. No. 1,180,334, published Feb. 4, 1970, by R. F. Pearson, et al., entitled "Optical Scanner."
The concept of placing a low anisotropy material within the high anisotropy material of a magnetic post element has been disclosed in a co-pending U.S. patent application, Ser. No. 320,819, filed Nov. 12, 1981, by Bruce E. MacNeal and William E. Ross, entitled "Altering The Switching Threshold Of A Magnetic Material," assigned to the same assignee as the present invention. In yet another co-pending application the concept of reducing the number of electrical conductors required to switch the direction of magnetization of magnetic post elements has been discussed. See, co-pending U.S. patent application Ser. No. 375,326, filed May 5, 1982, by Bruce E. MacNeal, entitled "Method And Device For Improving A Conductive Switching Grid For Magnetic Elements."
The MacNeal patent application teaches a method and device for eliminating every other electrical connector in either the X or Y direction of the grid-like pattern formed by separations between the magnetic post elements. However, this arrangement does not permit the elimination or reduction of conductors in both the X and Y directions.